Joseph Diaz Jr. has bounced back before. There’s no reason to think he can’t do it again.

“Jo Jo” lost a wide decision to quick, slick Gary Russell Jr. in 2018 only to win his next five fights, including a break-through unanimous decision over the favored Tevin Farmer to win the IBF 130-pound title in 2020.

Now he’s coming off another one-sided setback, this time against undisputed 135-pound champion Devin Haney last December, a loss that has led some to believe the 29-year-old’s best years are behind him.

Diaz (32-2-1, 15 KOs) aims to prove them wrong, starting with his comeback fight against Mexican slugger William Zepeda on Saturday in San Diego (DAZN).

“I’ve had a couple of losses, a couple of ups and downs in my career,” he told Boxing Junkie, “but I feel like my whole journey has made me the fighter I am today. They’ve made me more focused, more determined, hungrier.

“I used that energy in this training camp. I’m excited about Oct. 29.”

Zepeda (26-0, 23 KOs) could be a significant challenge for Diaz.

The 26-year-old is a fit, fierce warrior who has 23 knockouts in 26 fights for a reason: He can crack. Diaz expects Zepeda to attack him from the opening bell, which will almost be refreshing for the well-schooled American.

Diaz was the hunter against movers Farmer, Javier Fortuna and Haney. He’ll be the hunted against Zepeda.

“I don’t have to fight a guy I have to chase, like Farmer, Fortuna, Haney,” he said. “These guys fight on their back foot, trying to box, trying to move, being defensive. William Zepeda will apply a lot of pressure, which will allow me to show my boxing skills.

“I feel I’ll be able to be elusive, to show my skills, my defensive skills. Everything in my arsenal will come out on Saturday night.”

Plus, this being his fourth fight at 135 pounds, he feels he has grown into the division. His physical strength, he believes, will help him cope with the physical challenges Zepeda might present in their scheduled 12-rounder.

“I’ll have speed, elusiveness and power. You’ll see on Saturday night,” he said.

If things go well for Diaz, he hopes to move directly into another big fight.

That means a meeting with the likes of Haney, Gervonta Davis, Ryan Garcia or Shakur Stevenson, four of the most resected fighters in the world. All of them would be significant favorites to hand Diaz his third loss.

That perception wouldn’t faze Diaz, who has bucked the odds repeatedly in his career. His confidence has never wavered, even after setbacks.

He was asked how he was able to bounce back from the loss to Russell.

“A lot of determination, a lot of inner belief in myself,” he said. “I have that inner belief, trust in God, knowing everything I’ve been through. I believe I can overcome anything.”

Diaz’s critics might roll their eyes when they read that comment given his losses to Russell and Haney. Well, he insists the doubts work in his favor.

The 2012 U.S. Olympian said that his soon-to-be 2-year-old son is his primary source of motivation these days. After that comes those who don’t believe he has the ability to compete with the elite 135-pounders in spite of his credentials.

“The hatred fuels me,” he said. “A lot of people think I’ve fallen off, that I’m not the fighter I was. That right there motivates me. Like I said, I’ve had losses in my career. You can’t let that beat you. You just make adjustments the next time so you can be victorious. …

“I’m ready to perform.”